After giving a quick try, the first difference i see in openpak128 in comparison to pak128 is the terrain looks different : the ground has some grass texture , the slopes aren't those oddly/ugly rounded anymore and there's some kind of texture blending between the bottom and top of a slope
Other than that, so far i'm not seeing obvious differences, from my first oil field to power station, it seems to generate the same kind of profits.
Didn't tried other pak128 profitable routes to see if they're the same in openpak128
edit :
So i gave a try to a long chain ending in books, the only one available on my map anyways, using trains that aren't costing too much in running but aren't too slow and served me well in previous games.
1 train transporting lumber from tree plantation to paper mill .
1 train, using the same station from the paper mill (to try to avoid more maintenance as stations kills your monthly budget in pak128) transport paper to the printing work
1 train from an oil field to a refinery in order to get chemical, 1 train to transport said chemical to printing work (same printing work station to avoid again too much maintenance)
and finally 1 train from printing work (getting from the same station too) to publishing company for transporting the final product, the books.
I see there's an oil powerstation, so i add a train to transport oil to that powerstation, to improve my profits as powerstation are always profitable from past pak128 games.
All of that cost a very lot, and i am at -350k , i don't care as i am still at high positive net wealth anyways .
I then sit and wait with accelerated time .
After several months of seeing my losses getting bigger and bigger, i check my convoy, and nicely but surprisingly considering i see each months money being lost, every convoy generate profitable income, not all the same of course, some weaker income than other, but still positive income, profit.
Then not understanding why i'm still continuously losing money at best -1500 at worst -2500 a months, i check the finance.
maintenance and operation cost are just killing the whole network, can't understand why as i did made the most straight and shorter railroads possible for all those connections.
Oh well, back to pak64 as i noticed there's one for the nightlies too